A STUDY ON THE OCCURRENCE OF AFLATOXIN IN RAW MILK DUE TO FEEDS

Milk and milk products are the most important group of food which carries aflatoxin to the people. Therefore, the existence of aflatoxin M₁ (AFM₁) in milk is a potential risk for public health. AFM₁ existence in milk and milk products was found in studies performed in Turkey. In this study, aflatoxin contamination was detected in 48 raw milk and 48 feed samples. Milk and feed samples, in which the positive sample rate was determined as 24%, included different levels of aflatoxin. Altogether, 20 raw milk samples (41.67%) and 15 feed samples (31.25%) contained over the level of legal limits established by the Turkish Food Codex (TFC) and the European Communities (EC) regulation in positive samples. According to these results, the milk and feed samples collected from this area constitute a potential risk for public health. The most effective way of controlling aflatoxin M₁ in milk is to reduce the contamination of aflatoxin in raw milk and feed samples. Both the producers and the consumers, as well as the government, have important obligations on this subject.     

HYGIENIC PARAMETERS, TOXINS AND PATHOGEN OCCURRENCE IN RAW MILK CHEESES

In total, 71 samples of retail raw milk cheeses produced or imported in Belgium and samples of Belgian farmhouse cheeses were examined for cotiforms, β-glucuronidase positive Escherichia coli, Escherichia coli O157 , Staphylococcus aureus, Salmonella spp. , Listeria spp. and Listeria monocytogenes. The presence of staphylococcal enterotoxins was investigated on samples with S. aureus counts higher than 10³ cfu/g. The incidence of coliforms, β-glucuronidase positive E. coli and S. aureus was higher in soft than in blue veined, semi-hard, hard and fresh cheeses. Four mold-ripened soft cheeses were positive for E. coli O157. One of the 4 cheeses was positive for verotoxin VT2. Staphylococcal enterotoxins were detected in 1 soft redsmear cheese, which was positive for L. monocytogenes. L. monocytogenes was also detected in one fresh cheese . Salmonella was not detected in any of the 71 raw milk cheeses.     

THE OCCURRENCE OF CHROMIUM IN RAW MATERIALS AND ITS FATE IN THE BREWING PROCESS

The chromium content of raw materials, intermediate and final products in the brewing process were determined in order to evaluate the contribution of raw materials to the chromium content of beer. The contribution due to beer in the diet is considered in the light of the recommended daily intake of chromium.     

THE EFFECT OF STORAGE TEMPERATURE ON BACTERIAL GROWTH AND LIPOLYSIS IN RAW MILK

The temperature at which raw milk was stored, within the range 4°-8°C, affected the rate of growth of bacteria and the release of free fatty acids. The effects were of both statistical and practical significance and it was shown that, by maintaining milk temperatures at 4°C, a useful extension of the storage time of raw milk could be achieved. Lipolysis in stored milk was not closely related to the total concentration of psychrotrophic bacteria, but lipolytic rancidity was not observed when the psychrotroph count was below 5 × 10⁶ colony forming units/ml.     

A BELGIAN SURVEY OF HYGIENE INDICATOR BACTERIA AND PATHOGENIC BACTERIA IN RAW MILK AND DIRECT MARKETING OF RAW MILK FARM PRODUCTS

To monitor the bacteriological quality of raw milk and raw milk farm products, 143 samples of raw farm milk and 100 samples of raw milk farm products, 64 butters, 9 yogurts, 16 cheeses, 7 ice creams and 4 fresh cheeses, produced in Belgium were examined for coliforms, β-glucuronidase positive Escherichia coli, verotoxin producing Escherichia coli O157 , Staphylococcus aureus, Salmonella spp. , Listeria spp. and Listeria monocytogenes. The results were compared with the threshold and maximum values of the EC directive 92/46/EC or the maximum values of the Belgian Order of Council from September 3, 2000. The presence of staphylococcal enterotoxins was investigated on samples with S. aureus counts higher than the legal threshold values mentioned in the EC directive or, if not regulated in the directive, higher than the maximum value mentioned in the Belgian Order of Council. The obtained results for the hygiene-indicators coliforms, β-glucuronidase positive E. coli and S. aureus in the raw milk samples were comparable with most other industrialized countries. Compared to a prevalence of 0.7% and 6.3% for, respectively , E. coli O157 and L. monocytogenes, no Salmonella was found in the 25 g raw milk farm samples. The isolated E. coli O157 strain was confirmed to be verotoxigenic; it was positive for VT2 , eaeA and hly A. In butter not only a prevalence of 18.7% for L. monocytogenes in 25 g was found but also the maximum values for the hygiene-indicators mentioned in the Belgian Order of Council were often exceeded. No significant difference was found between the count of hygiene-indicators and the presence of Listeria spp. as well in raw milk as in raw milk butter. The bacteriological quality of on-farm made raw milk butter suggest that suitable hygienic conditions are not always provided. One of the 7 ice cream samples contained L. monocytogenes in 25 g.     

THE QUALITY OF BLENDED RAW MILK IN CREAMERIES IN SOUTH-WEST SCOTLAND

The quality of raw blended milk going to manufacture at five creameries in southwest Scotland has been surveyed over a two-year period. Analyses of gross composition, somatic cell count, numbers and types of bacteria present and the concentration of free fatty acid in the milk show that milk quality was of a high standard. However, extended storage of the milk at 6°C indicated that the bacteria in the milk were actively multiplying and the results showed that extended storage of milk at creameries could seriously jeopardize milk quality. The development of lipolysis on extended storage of the milks was associated with the numbers and types of bacteria present in the milk before storage.     

THE FUTURE OF UHT MILK AND MILK PRODUCTS IN EUROPE

The development of packed milk relative to total milk consumption in Switzerland from 1958-76 is illustrated and the future of the industry in Continental Europe considered. Decrease in milk consumption in both Switzerland and Germany and the limitations of climatic conditions and transport are discussed and the advantages of UHT long-life milk evaluated. The potential in an increasing market for UHT milk products and in aseptic filling machines is assessed. ( Editor's summary ).     

THE CHANGING ROLE OF MILK AND MILK PRODUCTS IN DIETS IN THE UNITED KINGDOM

The paper deals with: (1) The present contribution of milk in United Kingdom diets; (2) past changes in consumption; (3) factors affecting consumption; (4) how consumption can be changed; (5) likely future changes. One difficulty is that information on consumption refers to groups; little is known about individual consumption. This is even more true for past consumption patterns. Many factors affect consumption. A major part is played by government intervention, both in regulating prices and in distribution of welfare milk. Propaganda that milk fat is harmful has had little effect in this country. Future trends are difficult to forecast since they increasingly depend on government policy.     

THE NUTRITIONAL IMPORTANCE OF MILK AND MILK PRODUCTS IN THE NATIONAL DIET

The average consumption of milk and milk products is related to their composition and to the recommended intakes for nutrients, and the nutritional importance of dairy products is considered. The major contribution to the average diet is in the protein, calcium, riboflavin and vitamin A contained in dairy products.     

HIGH-PRESSURE DESTRUCTION KINETICS OF SPOILAGE AND PATHOGENIC BACTERIA IN RAW MILK CHEESE

Raw milk cheese samples were individually inoculated with Escherichia coli K‐12, Escherichia coli O157:H7 and Listeria monocytogenes, and subjected to high‐pressure (HP) treatments (200–400 MPa) in both pressure hold and pressure pulse modes. Pressure inactivation of E. coli K‐12 at 350 MPa (5 min) at different temperatures demonstrated a strong temperature effect when temperature was 40C and above. Pressure destruction kinetics and pressure sensitivity were evaluated at 25C (where the temperature effect was minimal). HP treatment generally demonstrated a step‐change pressure pulse effect followed by a holding time destruction that was well described by a first‐order model (R² > 0.90) with higher pressures resulting in a faster rate of microbial reduction (smaller D values). The associated D values at an intermediate pressure of 300 MPa were 4.4, 14.5 and 3.6 min for E. coli K‐12, E. coli O157:H7 and L. monocytogenes, respectively, with E. coli O157:H7 thus demonstrating a higher‐pressure resistance than the other two. The corresponding pressure z_p values were 156, 128 and 82 MPa, and ΔV^≠(Arrhenius volume change of activation) values were ?3.6, ?4.4 and ?7.0 (×10^?5 m³/mole), respectively. Pulse mode treatments showed similar pressure resistance trends to pressure hold mode, but were not effective for E. coli O157:H7.     

THE OCCURRENCE, HEMOLYTIC ACTIVITY AND ANTIBIOTIC SUSCEPTIBILITY OF MOTILE AEROMONAS SPP. ISOLATED FROM MEAT AND MILK SAMPLES IN TURKEY

Research was carried out to detect the incidence of motile Aeromonas species (A. hydrophila, A. caviae, A. sobria) in a variety of raw meat products (minced meat and chicken) and milk samples (raw and pasteurized) commonly consumed in Ankara. Motile Aeromonas species were isolated from 51.8% of samples detected; these were 40 (67.7%) of the 59 samples of minced meat, 20 (86.9%) of the 23 samples of chicken, 75 (47.7%) of the 157 samples of raw milk and 5 (16.0%) of the 31 samples of pasteurized milk. The dominant species were A.hydrophila and A.sobria in the meat samples, while A. hydrophila was the only isolated species in the milk samples. The strains identified as A. sobria or A. hydrophila were the stronger producers of hemolysin, whereas the A. caviae strains were nonhemolytic. The resistance of isolates to eight antibiotics was determined using the Kirby Bauer disc diffusion assay (Ciprofloxacin, Ceftazidime, Ampicillin, Cefixime, Cefoperazone, Erythromycin, Trimethoprim/sulfamethoxazole, Ceftriaxone). All aeromonads isolates (100%) were susceptible to ciprofloxacin but resistant to (100%) ampicillin and erythromycin. We found out that motile Aeromonas species are commonly present in milk and meat samples investigated in Turkey, which may pose a health problem to consumer. In addition, ciprofloxacin, cefoperozone, and ceftriaxone are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly in the immunocompromised, elderly people and young children.     

乳酸发酵型百合乳饮料工艺的研究

研究了以百合酶解液、鲜牛奶为主要原料，生产出一种纯天然保健乳饮料的工艺，并对加工过程中的护色、酶解和稳定剂的选择等进行了探讨，最终确立了产品的最优配方和生产工艺。     

春夏秋冬又一春

《纽约时报》曾经针对高级定制时装的命运发表评论：“每过十年．医生们都会围绕在法国高定的床边．宣布它即将离去的消息。但就像每一个与病魔斗争的人一样．坚强的意志使得高定一次次存活了下来。”